Device with a high efficiency voltage multiplier

ABSTRACT

A device includes a capacitive element that is coupled between first and second nodes and that includes a first well region, a second well region, and a transistor. The second well region is formed in the first well region, has a different conductivity type than the first well region, and is coupled to the second node. The transistor includes source and drain regions formed in the second well region and coupled to each other and to the second node, a channel region between the source and drain regions, and a gate region over the channel region. The first well region and the gate region are coupled to each other and to the first node, whereby a capacitance of the capacitive element is increased without substantially enlarging a physical size of the capacitive element.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. patentapplication Ser. No. 15/602,246, entitled “Device with a High EfficiencyVoltage Multiplier,” filed May 23, 2017, which is incorporated herein byreference in its entirety.

BACKGROUND

A device uses a voltage multiplier to generate a voltage higher than,e.g., twice, a supply voltage. For example, a device, such as a memorydevice, may read a memory cell at a read voltage equal to the supplyvoltage and write to the memory cell at a write voltage twice the supplyvoltage.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the present disclosure are best understood from the followingdetailed description when read with the accompanying figures. It isnoted that, in accordance with the standard practice in the industry,various features are not drawn to scale. In fact, the dimensions of thevarious features may be arbitrarily increased or reduced for clarity ofdiscussion.

FIG. 1 is a schematic diagram illustrating an exemplary device inaccordance with some embodiments.

FIG. 2 is a schematic diagram illustrating the relationship betweenfirst and second clock signals in accordance with some embodiments.

FIG. 3 is a flow chart illustrating an exemplary method of operation ofa device in accordance with some embodiments.

FIG. 4 is a schematic sectional view illustrating an exemplarycapacitive element in accordance with some embodiments.

FIG. 5 is a schematic diagram illustrating an equivalent circuit of acapacitive element in accordance with some embodiments.

FIG. 6 is a schematic diagram illustrating an exemplary device inaccordance with some embodiments.

FIG. 7 is a flow chart illustrating an exemplary method of operation ofa device in accordance with some embodiments.

DETAILED DESCRIPTION

The following disclosure provides many different embodiments, orexamples, for implementing different features of the provided subjectmatter. Specific examples of components and arrangements are describedbelow to simplify the present disclosure. These are, of course, merelyexamples and are not intended to be limiting. For example, the formationof a first feature over or on a second feature in the description thatfollows may include embodiments in which the first and second featuresare formed in direct contact, and may also include embodiments in whichadditional features may be formed between the first and second features,such that the first and second features may not be in direct contact. Inaddition, the present disclosure may repeat reference numerals and/orletters in the various examples. This repetition is for the purpose ofsimplicity and clarity and does not in itself dictate a relationshipbetween the various embodiments and/or configurations discussed.

Further, spatially relative terms, such as “beneath,” “below,” “lower,”“above,” “upper” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. The spatiallyrelative terms are intended to encompass different orientations of thedevice in use or operation in addition to the orientation depicted inthe figures. The apparatus may be otherwise oriented (rotated 90 degreesor at other orientations) and the spatially relative descriptors usedherein may likewise be interpreted accordingly.

The present disclosure provides a device, e.g., an integrated circuit,that in an exemplary embodiment includes a voltage multiplier, e.g.,voltage multiplier 140 of FIG. 1 . The voltage multiplier 140 iscontrolled by first and second clock signals, e.g., first and secondclock signals (CLK1, CLK2) in FIG. 2 , so as to generate a load voltage,e.g., 0.8V, higher than, e.g., about twice, a supply voltage, e.g.,0.4V, for driving a load. The voltage multiplier 140 includes a firstcapacitive element (C1). Efficiency of the voltage multiplier 140 can beimproved by increasing a capacitance of the first capacitive element(C1), e.g., via capacitive element construction.

In further detail, FIG. 1 is a schematic diagram illustrating anexemplary device 100 in accordance with some embodiments. The exampledevice 100 includes a supply node 110, a reference node 120, a load node130, and a voltage multiplier 140. The supply node 110 is configured toreceive a supply voltage (Vdd), e.g., 0.4V. The reference node 120 isconfigured to receive a reference voltage (Vss), e.g., 0V, lower thanthe supply voltage (Vdd). The voltage multiplier 140 includes first andsecond nodes (N1, N2), first and second capacitive elements (C1, C2),first and second switch units 150, 160.

The first capacitive element (C1), e.g., a metal-oxide semiconductorcapacitor (MOSCAP), a metal-insulator-metal (MIM) capacitor, or othertype of capacitor, is connected between the first and second nodes (N1,N2). The first switch unit 150 includes first and second switches (SW1,SW2) and is configured to receive a first clock signal (CLK1) thatcontrols operations of the first and second switches (SW1, SW2). Thefirst switch (SW1) is connected between the supply node 110 and thefirst node (N1) and is operable so as to selectively connect anddisconnect the first node (N1) to and from the supply node 110. Thesecond switch (SW2) is connected between the second node (N2) and thereference node 120 and is operable so as to selectively connect anddisconnect the second node (N2) to and from the reference node 120.

Similarly, the second switch unit 160 includes third and fourth switches(SW3, SW4) and is configured to receive a second clock signal (CLK2)that controls operations of the third and fourth switches (SW3, SW4).The third switch (SW3) is connected between the supply node 110 and thesecond node (N2) and is operable so as to selectively connect anddisconnect the second node (N2) to and from the supply node 110. Thefourth switch (SW4) is connected between the first node (N1) and theload node 130 and is operable so as to selectively connect anddisconnect the first node (N1) to and from the load node 130. In thisembodiment, the switches (SW1-SW4) are n-type field-effect transistors(FETs). In some embodiments, one of the switches (SW1-SW4) is a p-typeFET. In other embodiments, one of the switches (SW1-SW4) is any sort oftransistor, e.g., a bipolar junction transistors (BJT), or other type ofswitch.

The second capacitive element (C2), e.g., a MOSCAP, a MIM capacitor, orother type of capacitor, is connected between the load node 130 and thereference node 120.

A load 190 is connected across the second capacitive element (C2). Theload 190 is, in an exemplary embodiment, a time-to-digital converter(TDC) that converts time information into a digital code. For example,the TDC 190 may output a series of l's and 0's indicating levels ofsignals at a certain point in time. Such a circuit may be useful in anall-digital phase lock loop (ADPLL) system. In some embodiments, thedevice 100 includes the load 190. In other embodiments, the device 100does not include the load 190 and the load 190 may be connected to theload node 130 externally of the device 100.

FIG. 2 is a schematic diagram illustrating the relationship between thefirst and second clock signals (CLK1, CLK2) in accordance with someembodiments. Each of the first and second clock signals (CLK1, CLK2)alternates between a low signal level, e.g., reference voltage (Vss)level, and a high signal level, e.g., twice the supply voltage (Vdd)level. In the example of the FIG. 2 , the high signal levels of thefirst clock signal (CLK1) and the high signal levels of the second clocksignal (CLK2) do not overlap with each other in time. That is, asillustrated in FIG. 2 , there is a time (t1) between a falling/risingedge of the first clock signal (CLK1) and a rising/falling edge of thesecond clock signal (CLK2). As will be apparent from the discussionwhich follows, the time (t1) is determined to ensure that the durationthereof, e.g., about 0.5 μs, is long enough so that falling/rising edgesof the first clock signal (CLK1) and rising/falling edges of the secondclock signal (CLK2) do not overlap, preventing short-circuiting of thesupply node 110 and the reference node 120. The time (t1) is furtherdetermined to ensure that the duration thereof is short enough so thatthe load 190 is driven at a substantially constant load voltage(V_(LOAD)) by the voltage multiplier 140.

FIG. 3 is a flow chart illustrating an exemplary method 300 of operationof the device 100 in accordance with some embodiments. The examplemethod 300 is described with further reference to FIG. 1 for ease ofunderstanding. It should be understood that method 300 is applicable tostructures other than that in FIG. 1 . In operation 310, the firstswitch unit 150 receives the first clock signal (CLK1) and the secondswitch unit 160 receives the second clock signal (CLK2).

After a time (t1), in operation 320, the first clock signal (CLK1)transitions from a low signal level to a high signal level and controlsthe first switch (SW1) to connect the first node (N1) to the supply node110 and the second switch (SW2) to connect the second node (N2) to thereference node 120. This connects the first capacitive element (C1)between the supply node 110 and the reference node 120, charging thefirst capacitive element (C1) to the supply voltage (Vdd). At this time,the second clock signal (CLK2) is at the low signal level and controlsthe third switch (SW3) to disconnect the second node (N2) from thesupply node 110 and the fourth switch (SW4) to disconnect the first node(N1) from the load node 130.

Next, the first clock signal (CLK1) transitions back to the low signallevel and controls the first switch (SW1) to disconnect the first node(N1) from the supply node 110 and the second switch (SW2) to disconnectthe second node (N2) from the reference node 120. After a time (t1), inoperation 330, the second clock signal (CLK2) transitions from the lowsignal level to the high signal level and controls the third switch(SW3) to connect the second node (N2) to the supply node 110 and thefourth switch (SW4) to connect the first node (N1) to the load node 130.This connects the first capacitive element (C1) between the supply node110 and the load node 130, providing a load voltage (Vload)substantially equal to the sum of the supply voltage (Vdd) and a chargedvoltage across the first capacitive element (C1) at the load node 130.This, in turn, charges the second capacitive element (C2) to the loadvoltage (Vload). As a result, the load 190 is driven at the load voltage(Vload) about twice the supply voltage (Vdd).

From an experimental result, at a given current, e.g., 400 uA, flowingthrough the load 190, the device 100 provides a substantially constantload voltage (Vload), e.g., about 91% to about 99% of two times thesupply voltage (Vdd), and a relatively small ripple voltage, e.g., about20 mV to about 30 mV. Further, the device 100 outputs the load voltage(Vload) within a short period of time, e.g., 8 μs, after the device 100receives the supply voltage (Vdd).

As noted above, capacitance of a capacitive element (e.g., C1) can beinfluenced by capacitive element construction. FIG. 4 is a schematicsectional view illustrating an exemplary first capacitive element (C1)in accordance with some embodiments. The first capacitive element (C1)includes a substrate 410, first and second well regions 420, 430, and atransistor 440. The substrate 410 has a p-type conductivity and isconnected to the reference node 120. The substrate 410 may includesilicon, germanium, other semiconductor material, or a combinationthereof. The first well region 420 is formed, such as by implantation,in a portion of the substrate 410. The first well region 420 may includethe same material as the substrate 410, but is doped with n-typeimpurities and thus have an n-type conductivity. FIG. 5 is schematicdiagram illustrating an exemplary equivalent circuit of the firstcapacitive element (C1) in accordance with some embodiments. As can beseen from FIG. 5 , because the substrate 410 and the first well region420 have different conductivity types, the substrate 410 and the firstwell region 420 cooperatively form a diode (D1).

The second well region 430 is implanted in a portion of the first wellregion 420, includes the same material as the substrate 410, and has ap-type conductivity. The first well region 420 extends deeper into thesubstrate 410 than the second well region 430. As can be seen from FIG.5 , because the first well region 420 and the second well region 430have different conductivity types, the first well region 420 and thesecond well region 430 cooperatively form a diode (D2) connected to thediode (D1).

The transistor 440 is over the second well region 430 and includessource and drain regions 440 a, 440 b that has an n-type conductivityand that are implanted in the second well region 430. The transistor 440further includes a gate region 440 c over a channel region between thesource and drain regions 440 a, 440 b. As can be seen from FIG. 5 ,because the source and drain regions 440 a, 440 b are connected to eachother and to the second node (N2), the first capacitive element (C1) isformed by the transistor 440. The second well region 430 is connected tothe second node (N2) so as not to leave the second well region 430floating. The first well region 420 and the gate region 440 c areconnected to each other and to the first node (N1). This results in anincreased capacitance for the first capacitive element (C1), e.g., about10% from a capacitance thereof when the first well region 420 and thegate region 440 c are disconnected from each other, without enlarging aphysical size of the first capacitive element (C1), improving anefficiency of the device 100, for as much as 12%.

FIG. 6 is a schematic diagram illustrating an exemplary device 600 inaccordance with some embodiments. This embodiment differs from theprevious embodiment in that the example device 600 further includes aclock generator 610 and a second voltage multiplier 620. The clockgenerator 610 is connected between a feedback node 630 and the referencenode 120 and includes first and second modules (not shown). The firstmodule, e.g., a cross-coupled flip-flop, is configured to receive aninput signal (IN) and to generate the first and second clock signals(CLK1, CLK2) that each correspond to the input signal (IN) and alternatebetween a low signal level, e.g., reference voltage (Vss) level, and ahigh signal level, e.g., level of a feedback voltage (Vfeedback) at thefeedback node 630. The second module is configured to introduce a delay,i.e., the time (t1), between a falling/rising edge of the first clocksignal (CLK1) and a rising/falling edge of the second clock signal(CLK2). In an implementation, the second module includes a pair ofinverters connected in series.

The voltage multiplier 140 is connected to the clock generator 610, isconfigured to receive the first and second clock signals (CLK1, CLK2)and, as described above, is controlled by the first and second clocksignals (CLK1, CLK2) so as to generate a load voltage (Vload) higherthan, e.g., about twice, the supply voltage (Vdd) for driving the load190.

The second voltage multiplier 620 is connected to the clock generator610, is configured to receive the first and second clock signals (CLK1,CLK2), and is controlled by the first and second clock signals (CLK1,CLK2) so as to generate the feedback voltage (Vfeedback) higher than,e.g., about twice, the supply voltage (Vdd) for driving the clockgenerator 610.

In further detail, a switch (D3), e.g., one or more diodes, is connectedbetween the supply node 110 and the feedback node 630. The switch (D3)connects the feedback node 630 to the supply node 110, e.g., is forwardbiased, when the feedback voltage (Vfeedback) is less than the supplyvoltage (Vdd), and disconnects the feedback node 630 from the supplynode 110, e.g., is reversed biased, when the feedback voltage(Vfeedback) increases to greater than the supply voltage (Vdd). In anembodiment, the switch (D3) includes one or more diode-connected FETs,any sort of diode, or other type of switch.

The second voltage multiplier 620 includes third and fourth nodes (N3,N4), third and fourth capacitive elements (C3, C4), and third and fourthswitch units 640, 650. The third capacitive element (C3) is connectedbetween the third and fourth nodes (N3, N4). In this embodiment, thethird capacitive element (C3) has a structure similar to that describedabove in connection with the first capacitive element (C1). The thirdswitch unit 640 includes fifth and sixth switches (SW5, SW6), isconnected to the clock generator 610, and is configured to receive thefirst clock signal (CLK1) that controls operations of the fifth andsixth switches (SW5, SW6). The fifth switch (SW5) is connected betweenthe supply node 110 and the third node (N3) and is operable so as toselectively connect and disconnect the third node (N3) to and from thesupply node 110. The sixth switch (SW6) is connected between the fourthnode (N4) and the reference node 120 and is operable so as toselectively connect and disconnect the fourth node (N4) to and from thereference node 120.

Similarly, the fourth switch unit 650 includes seventh and eighthswitches (SW7, SW8), is connected to the clock generator 610, and isconfigured to receive the second clock signal (CLK2) that controlsoperations of the seventh and eighth switches (SW7, SW8). The seventhswitch (SW7) is connected between the supply node 110 and fourth node(N4) and is operable so as to selectively connect and disconnect thefourth node (N4) to and from the supply node 110. The eighth switch(SW8) is connected between the third node (N3) and the feedback node 630and is operable so as to selectively connect and disconnect the thirdnode (N3) to and from the feedback node 630. In this embodiment, theswitches (SW5-SW8) are n-type FETs. In some embodiments, at least one ofthe switches (SW5-SW8) is a p-type FET. In other embodiments, at leastone of the switches (SW5-SW8) is any sort of transistor, e.g., a BJT, orother type of switch.

The fourth capacitive element (C4), e.g., a MOSCAP, a MIM capacitor, orother type of capacitor, is connected between the feedback node 630 andthe reference node 120.

As will be apparent from the discussion which follows, the time (t1) isdetermined to ensure that the duration thereof is long enough so thatfalling/rising edges of the first clock signal (CLK1) and rising/fallingedges of the second clock signal (CLK2) do not overlap, preventingshort-circuiting of the supply node 110 and the reference node 120.Further, the time (t1) is determined to ensure that the duration thereofis short enough so that the clock generator 610 is driven at asubstantially constant feedback voltage (Vfeedback) by the secondvoltage multiplier 620. FIG. 7 is a flow chart illustrating an exemplarymethod 700 of operation of the device 600 in accordance with someembodiments. The example method 700 is described with further referenceto FIG. 6 for ease of understanding. It should be understood that method700 is applicable to structures other than that in FIG. 6 . In operation710, the switch (D3) connects the feedback node 630 to the supply node110.

In operation 720, the feedback node 630 receives a feedback voltage(Vfeedback) less than the supply voltage (Vdd), e.g., substantiallyequal to the difference between the supply voltage (Vdd) and a voltagedrop across the switch (D3). In operation 730, the clock generator 610receives an input signal (IN) and generates the first and second clocksignals (CLK1, CLK2). In operation 740, the third switch unit 640receives the first clock signal (CLK1) and the fourth switch unit 650receives the second clock signal (CLK2).

After a time (t1), in operation 750, the first clock signal (CLK1)transitions from a low signal level to a high signal level and controlsthe fifth switch (SW5) to connect the third node (N3) to the supply node110 and the sixth switch (SW6) to connect the fourth node (N4) to thereference node 120. This connects the third capacitive element (C3)between the supply node 110 and the reference node 120, charging thethird capacitive element (C3) to the supply voltage (Vdd). At this time,the second clock signal (CLK2) is at the low signal level and controlsthe seventh switch (SW7) to disconnect the fourth node (N4) from thesupply node 110 and the eighth switch (SW8) to disconnect the third node(N3) from the feedback node 630.

Next, the first clock signal (CLK1) transitions back to the low signallevel and controls the fifth switch (SW5) to disconnect the third node(N3) from the supply node 110 and the sixth switch (SW6) to disconnectthe fourth node (N4) from the reference node 120. After a time (t1), inoperation 760, the second clock signal (CLK2) transitions from the lowsignal level to the high signal level and controls the seventh switch(SW7) to connect the fourth node (N4) to the supply node 110 and theeighth switch (SW8) to connect the third node (N3) to the feedback node630. This connects the third capacitive element (C3) between the supplynode 110 and the feedback node 630, increasing the feedback voltage(Vfeedback) to substantially the sum of the supply voltage (Vdd) and thecharged voltage across the third capacitive element (C3). This, in turn,charges the fourth capacitive element (C4) to the feedback voltage(Vfeedback). In operation 770, the switch (D3) disconnects the feedbacknode 630 from the supply node 110 when the feedback voltage (Vfeedback)increases to greater than the supply voltage (Vdd). As a result, theclock generator 610 is driven at the feedback voltage (Vfeedback) abouttwice the supply voltage (Vdd), thereby enabling the clock generator 610to generate the first and second clock signals (CLK1, CLK2), each ofwhich alternates between a low signal level, e.g., reference voltage(Vss) level, and a high signal level, e.g., twice the supply voltage(Vdd) level.

As described above, the second voltage multiplier 620 enables the clockgenerator 610 to generate first and second clock signals (CLK1, CLK2)that have a high signal level greater than the supply voltage (Vdd)level. In some embodiments, method 700 further includes operations310-330 of method 300. In such some embodiments, the voltage multiplier140 uses the first and second clock signals (CLK1, CLK2) output by theclock generator 610 to generate the load voltage (Vload) greater thanthe supply voltage (Vdd) at which the voltage multiplier 140 operates.As such, in other embodiments, the voltage multiplier 140 may bereplaced with a circuit so long that it operates at a supply voltage(Vdd) and at a clock signal, a level of which is greater than the supplyvoltage (Vdd) level.

In an alternative embodiment where the load 190 is light and does notdraw as much load current as a heavy load, the device 600 does notinclude the voltage multiplier 140 and the load 190 is connected to thefeedback node 630. That is, in such an alternative embodiment, thesecond voltage multiplier 620 is configured to drive both the load 190and the clock generator 610 at a voltage greater than, e.g., twice, thesupply voltage (Vdd).

In an embodiment, a device comprises a capacitive element that iscoupled between first and second nodes and that includes a first wellregion, a second well region, and a transistor. The second well regionis formed in the first well region, has a different conductivity typethan the first well region, and is coupled to the second node. Thetransistor includes source and drain regions formed in the second wellregion and coupled to each other and to the second node, a channelregion between the source and drain regions, and a gate region over thechannel region. The first well region and the gate region are coupled toeach other and to the first node.

In another embodiment, a device comprises a clock generator and avoltage multiplier. The clock generator is coupled between a feedbacknode and a reference node and is configured to generate a clock signalthat alternates between a level of a feedback voltage at the feedbacknode and a level of a reference voltage at the reference node. Thevoltage multiplier includes a capacitive element and a switch unit. Thecapacitive element is coupled between first and second nodes. The switchunit is controlled by the clock signal so as to selectively couple thesecond node to a supply node and the first node to the feedback node,thereby increasing the feedback voltage to substantially the sum of asupply voltage at the supply node and a charged voltage across thecapacitive element.

In another embodiment, a method comprises: coupling a feedback node to asupply node; the feedback node receiving a feedback voltage less than asupply voltage at the supply node; generating a clock signal; and theclock signal controlling a switch unit to couple a capacitive elementbetween the supply node and the feedback node, thereby increasing thefeedback voltage to greater than the supply voltage.

The foregoing outlines features of several embodiments so that thoseskilled in the art may better understand the aspects of the presentdisclosure. Those skilled in the art should appreciate that they mayreadily use the present disclosure as a basis for designing or modifyingother processes and structures for carrying out the same purposes and/orachieving the same advantages of the embodiments introduced herein.Those skilled in the art should also realize that such equivalentconstructions do not depart from the spirit and scope of the presentdisclosure, and that they may make various changes, substitutions, andalterations herein without departing from the spirit and scope of thepresent disclosure.

The invention claimed is:
 1. A device comprising: a first voltagemultiplier configured to generate a load voltage and comprising: a firstcapacitive element including first and second nodes; a second capacitiveelement being coupled between load and reference nodes of the device; afirst switch coupling the first node to a supply node of the device andenabling the first capacitive element to be charged to a supply voltageat the supply node, the first switch operable to selectively connect anddisconnect the first node to and from the supply node, wherein there isno load coupled between the first node and the reference node; a secondswitch coupling the second node to the reference node and operable toselectively connect and disconnect the second node to and from thereference node; a third switch coupling the second node to the supplynode and operable to selectively connect and disconnect the second nodeto and from the supply node; and a fourth switch coupling the first nodeto the load node and operable to selectively connect and disconnect thefirst node to and from the load node; a load coupled to the load nodeand driven at a voltage comprising a sum of the supply voltage and avoltage across the first capacitive element; a second voltage multiplierconfigured to generate a feedback voltage and comprising: a thirdcapacitive element including third and fourth nodes; a fifth switchcoupling the third node to the supply node and operable to selectivelyconnect and disconnect the third node to and from the supply node; asixth switch coupling the fourth node to the reference node and operableto selectively connect and disconnect the fourth node to and from thereference node; a seventh switch coupling the fourth node to the supplynode and operable to selectively connect and disconnect the fourth nodeto and from the supply node; and an eighth switch coupling the thirdnode to a feedback node and operable to selectively connect anddisconnect the third node to and from the feedback node; a clockgenerator coupled to the feedback node and comprising a first moduleconfigured to generate first and second clock signals that eachalternate between a voltage at the reference node and a voltage at thefeedback node and a second module configured to introduce a timing delaybetween the first and second clock signals, the first clock signalcontrolling operation of the first, second, fifth, and sixth switches,and the second clock signal controlling operation of the third, fourth,seventh, and eighth switches; and a ninth switch coupled between thesupply node and the feedback node and configured to connect the feedbacknode to the supply node when the feedback voltage is less than thesupply voltage and to disconnect the feedback node from the supply nodewhen the feedback voltage increases to greater than the supply voltage,wherein the clock generator is only coupled to the supply node throughthe ninth switch.
 2. The device of claim 1, wherein the load is coupledbetween the load node and the reference node.
 3. The device of claim 1,wherein the second voltage multiplier further comprises a fourthcapacitive element coupled between the feedback node and the referencenode.
 4. The device of claim 1 wherein the load is a time-to-digitalconvertor, and the device further comprises: a transistor includingsource and drain regions formed in a second well region and coupled toeach other and to the second node of the first capacitive element, achannel region between the source and drain regions, and a gate regionover the channel region, wherein a first well region and the gate regionare coupled to each other and to the first node of the first capacitiveelement.
 5. The device of claim 1 wherein the first and secondcapacitive elements are capacitors, and the first capacitive element isa different type of capacitor than the second capacitive element.
 6. Thedevice of claim 1 wherein the second module includes a plurality ofinverters connected in series.
 7. A device comprising: a first voltagemultiplier configured to generate a load voltage and comprising: a firstcapacitive element between a first node and a second node and includinga first well region, and a second well region formed in the first wellregion, having a different conductivity type than the first well region,and coupled to the second node of the first capacitive element; a secondcapacitive element coupled between a load node and a reference node andconfigured to be charged to a load voltage; a first switch unit, whereinthe first switch unit comprises a first switch and a second switch,wherein the first switch is configured so as to selectively connect anddisconnect the first node of the first capacitive element to and from asupply node, and wherein the second switch is configured so as toselectively connect and disconnect the second node of the firstcapacitive element to and from the reference node, wherein there is noload coupled between the first node of the first capacitive element andthe reference node, thereby charging the first capacitive element to asupply voltage at the supply node; a second switch unit, wherein thesecond switch unit comprises a third switch and a fourth switch, whereinthe third switch is configured so as to selectively connect anddisconnect the second node of the first capacitive element to and fromthe supply node, and wherein the fourth switch is configured so as toselectively connect and disconnect the first node of the firstcapacitive element to and from the load node, whereby a load coupledbetween the load node and the reference node is driven at the loadvoltage substantially equal to the sum of the supply voltage and acharged voltage across the first capacitive element; a second voltagemultiplier configured to generate a feedback voltage and comprising: athird capacitive element coupled between third and fourth nodes; a thirdswitch unit, wherein the third switch unit comprises a fifth switchcoupling the third node to the supply node and operable to selectivelyconnect and disconnect the third node to and from the supply node and asixth switch coupling the fourth node to the reference node and operableto selectively connect and disconnect the fourth node to and from thereference node; and a fourth switch unit, wherein the fourth switch unitcomprises a seventh switch coupling the fourth node to the supply nodeand operable to selectively connect and disconnect the fourth node toand from the supply node and an eighth switch coupling the third node toa feedback node and operable to selectively connect and disconnect thethird node to and from the feedback node; a clock generator coupled tothe feedback node and comprising a first module configured to generate afirst clock signal and a second clock signal and a second moduleconfigured to introduce a timing delay between the first and secondclock signals, wherein each of the first and the second clock signalsalternates between a level of a reference voltage at the reference nodeand a level of a feedback voltage at the feedback node and controlsoperation of a respective one of the first and second switch units; anda fifth switch unit coupled between the supply node and the feedbacknode and configured to connect the feedback node to the supply node whenthe feedback voltage is less than the supply voltage and to disconnectthe feedback node from the supply node when the feedback voltageincreases to greater than the supply voltage, wherein the clockgenerator is only coupled to the supply node through the fifth switchunit; wherein the first, second, fifth, and sixth switches areconfigured to be controlled by the first clock signal; and wherein thethird, fourth, seventh, and eight switches are configured to becontrolled by second clock signal.
 8. The device of claim 7 wherein thesecond module includes a plurality of inverters connected in series. 9.The device of claim 7 wherein the first capacitive element furtherincludes a substrate.
 10. The device of claim 9 wherein the first andsecond well regions extend into the substrate.
 11. The device of claim 9wherein the first well region extends deeper into the substrate than thesecond well region.
 12. The device of claim 9 wherein the second wellregion and the substrate are comprised of the same material.
 13. Thedevice of claim 9 wherein the first well region, the second well region,and the substrate cooperatively form at least one diode.
 14. A methodcomprising: deploying a first capacitive element; deploying at least afirst switch unit, a second switch unit, a third switch unit, a fourthswitch unit, and a fifth switch unit; coupling a feedback node to asupply node; the feedback node receiving a feedback voltage less than asupply voltage at the supply node; deploying a clock generator coupledto the feedback node and comprising a first module configured togenerate a first clock signal and a second clock signal and a secondmodule configured to introduce a timing delay between the first andsecond clock signals, wherein each of the first and the second clocksignals alternates between a level of a reference voltage at a referencenode and a level of the feedback voltage at the feedback node andcontrols operation of a respective one of the first and second switchunits; generating the first clock signal; generating the second clocksignal; the first clock signal controlling the first switch unit tocouple the first capacitive element between the supply node and thereference node, thereby charging the first capacitive element to thesupply voltage; deploying a second capacitive element coupled between aload node and the reference node and configured to be charged to a loadvoltage; deploying a third capacitive element coupled between third andfourth nodes; wherein the first switch unit comprises a first switch anda second switch, wherein the first switch is configured so as toselectively connect and disconnect a first node of the first capacitiveelement to and from the supply node, and wherein the second switch isconfigured so as to selectively connect and disconnect a second node ofthe first capacitive element to the reference node, thereby charging thefirst capacitive element to the supply voltage at the supply node; thesecond clock signal controlling the second switch unit to couple thefirst capacitive element and the second capacitive element between thesupply node and the reference node, thereby charging the secondcapacitive element to about twice the supply voltage; wherein the secondswitch unit further comprises a third switch and a fourth switch,wherein the third switch is configured so as to selectively connect anddisconnect the second node of the first capacitive element to and fromthe supply node, and wherein the fourth switch is configured so as toselectively connect and disconnect the first node of the firstcapacitive element to and from the load node, whereby a load coupledbetween the load node and the reference node is driven at a load voltagesubstantially equal to the sum of the supply voltage and a voltageacross the first capacitive element; wherein the third switch unitcomprises a fifth switch coupling a third node of a third capacitiveelement to the supply node and operable to selectively connect anddisconnect the third node to and from the supply node and a sixth switchcoupling a fourth node of the third capacitive element to the referencenode and operable to selectively connect and disconnect the fourth nodeto and from the reference node; wherein the fourth switch unit comprisesa seventh switch coupling the fourth node to the supply node andoperable to selectively connect and disconnect the fourth node to andfrom the supply node and an eighth switch coupling the third node to thefeedback node and operable to selectively connect and disconnect thethird node to and from the feedback node; wherein the first, second,fifth, and sixth switches are configured to be controlled by the firstclock signal, wherein the third, fourth, fifth, and sixth switches areconfigured to be controlled by the second clock signal; wherein thefifth switch unit is configured to connect the feedback node to thesupply node when the feedback voltage is less than the supply voltageand to disconnect the feedback node from the supply node when thefeedback voltage increases to greater than the supply voltage; andwherein the clock generator is only connected to the supply node throughthe fifth switch unit.
 15. The device of claim 1, wherein the firstcapacitive element comprises: a first well region, a second well regionformed in the first well region, having a different conductivity typethan the first well region, and coupled to the second node of the firstcapacitive element, and a transistor including source and drain regionsformed in the second well region and coupled to each other and to thesecond node of the first capacitive element, a channel region betweenthe source and drain regions, and a gate region over the channel region,wherein the first well region and the gate region are coupled to eachother and to the first node of the first capacitive element.
 16. Thedevice of claim 1, wherein the ninth switch includes one or more diodes.17. The device of claim 1, further comprising a second load coupled tothe feedback node.
 18. The device of claim 1, wherein the first moduleincludes a cross-coupled flip-flop.
 19. The device of claim 7, whereinthe fifth switch includes one or more diodes.
 20. The method of claim14, further comprising: forward biasing the fifth switch unit when thefeedback voltage is less than the supply voltage; and reverse biasingthe fifth switch unit when the feedback voltage increases to greaterthan the supply voltage.